You hate the sight of him
Him breathing the same air as you but is it really hate you hold for him, or is it love masked under it all.
Under the word enemy. Yudam has always had mixed feelings about his enemy but never really got the time to show it since Dongbaek liked cat fights so much.
So in the midst of it all, it's easier to keep on falling for your sworn enemies cause who said enemies can't fall in love.